Improvement in door-clamps



'UNITED STATES PATENT OEETcE,

HENRYO. HOOPER, OF DIAMOND SPRINGS, CALIFOBIA.

IMPROVEMENT IN DOOR-CLAM PS.

y Specification forming part of Letters Patent No. 112,342, dated March7, 1871.

To all whom it may concern.-

Be it known that I, HENRY O. HOOPER, of Diamond Springs, county of ElDorado, State of California, have invented certain new and usefulImprovements in Door-Clamps 5 and I do hereby declare the `followingdescription and accompanying drawings are suicient to enable any personskilled in the art or science to which it most nearly appertains to makeand use my said invention or improvements Without further invention-orexperiment.

My present invention has for its object an improvement in door-clamps gand it relates more especially to a doorfclamp for which Letters Patentwere granted to me, No. 92,531,

`and dated July 13, 1869.

It consists in so forming the movable side pieces of the clamp whichholds the door, andv their operating screws and gears, that these sidepieces shall be moved equally at the top and bottom, and not necessitatean extension of those pieces down throughthe door, as is practically thecase in the former machine.

Referring to the accompanying drawing for a more complete explanation ofmy invention, Figure 1 is an 4end view, and Fig. 2 is a side elevation.

A is the bed or licor which the cross-beams Brest. The upright posts Care fitted so as to slide at the bottom on the guiding-beams B, or theymay travel On rollers, if desired. At the top of the posts C are placed,longitudinally, the bars D, which serve to support the door.

The projections or lugs E, which rise above the edge of the door as itlies, serve to clamp it when the sides D are moved toward each other.

The sides of the clamp are Operated by two screw-bars, F, at each end,one pair extending through the upper part and the other pair through thelower part of the posts C. u Nuts are firmly secured in the posts foreach" l of the screws to pass through, and thethreads of each screw aremade either right or left hand, according to their position, so thatwhen they are turned the sides may be brought simultaneously toward eachother, Or separated, as desired.

At or near -the center of each of the four screw-bars Fis placed aworms/heel, G, the two wheels at either end coming near enough 4togetherto be both operated by the same Worm or screw H. By this arrangementonly two worms are needed to Operate thc top and bottom of both clamps,and these are placed at the ends of a shaft, I. This shaft is suitablysupported by the central posts, J, within which the worms turn andthrough which the screw-bars pass, as shown.

The shaftI is turned by a belt which passes around the pulley K, and itsmotion can be reversed, to separate the sides by a cross-belt, upon thesame pulley. By this arrangement I am enabled to insure a perfectlyparallel movement of the clamps, so that, whether widely separated ornear together, the clamps will always stand vertically, and will thushold the door more securely.

I am also enabled to dispense with the eX- tensi'on of the posts C,which were formerlyaecessary in a practical machine.

Having thus described my invention, what I claim, and desire to secureby Letters Patent, is

The upper and lower sets of worm-wheels G, upon their respectivescrew-rods F, to gether with the shaft I and the worms H, whenconstructed to operate upon the posts C of the clamp, substantially asand for the purpose described.

In witness that the above-described invention is claimed by me I havehereunto set my hand and seal.

HENRY O. HOOPEB. [L. s] Witnesses:

JOHN L. BOONE, GEO. H. STRONG.'

